This paper proposes a new way of flipping small group classes in quantitative courses by active reading and peer marking using the virtual learning environment. We aim to engage students in the learning material by attempting a problem followed by peer marking based on some given solution guideline before they are exposed to another similar problem to solve during the small group classes. We design a quasi-experiment to evaluate the effect of peer marking by introducing an incentive in one such problem set and not in the other. The solution to the class problem is to act as the ‘incentive’, to be released only to the participants of the peer assessment. Using the data of two units from two UK universities and ‘incentives’ as instrumental variables to participation, our quantitative findings reveal the effect of participating in one more peer marking as a 3% increase in final marks on average. The qualitative analysis based on focus group discussions shows that the process increases student engagement, satisfaction, confidence and overall learning responsibility. The challenges often lie to establish a clear understanding of the purpose and the process of peer marking to ensure student buy-in to the system